March Express - new findings (1)

The new science of the old European spacecraft orbiting Mars

atmosphere
During the observations of the Mars Express spacecraft, it was discovered that the atmosphere of Mars contains ozone with a special spatial distribution(1). The findings show that the ozone is arranged in an array of three distinct layers, each with its own characteristics. A comparison between the findings and computer models shows how the circulation of the atmosphere creates an ozone layer over the South Pole during the winter season. On Earth, the ozone molecules are broken down by the sun's ultraviolet radiation and by chemical reactions with the hydrogen released from the decomposition of water vapor. The concentration of ozone in the atmosphere of Mars is 300 times smaller than that of the Earth.

Two of the ozone layers were discovered in low and middle latitudes. One layer is found below a height of 30 km from the ground. The second layer is found only in spring and summer in the Northern Hemisphere and varies at altitudes between 30 and 60 km from the ground. The third layer between 40 and 60 km high is found above the South Pole only in the winter season and has no equivalent in the winter in the Northern Hemisphere. That this layer is delimited between the latitude 75 degrees south and the south pole. The height of the layer is between 35 km and 70 km. The concentration of ozone gradually increases up to an altitude of 50 km until mid-winter, and then gradually decreases until it is undetectable at an altitude above 35 km. According to the researchers' assessment, the ear layer in the polar atmosphere is a product of an atmospheric circulation pattern that creates an oxygen emission detected at night at the pole. This circulation takes the form of a large Hadley cell where warm air rises up and moves towards the pole. The air then cools and sinks. in high latitudes. According to the researchers' assessment, this is a process in which there was a large vertical downward drop of oxygen-rich air brought from the hemisphere during the summer season. The oxygen atoms formed following the decomposition of the 2 CO in the upper part of the Hadley cell eventually combine at night at the pole to form oxygen molecules (2O) and ozone. The degree of concentration of ozone at night depends on the supply of oxygen and the rate of decomposition of water vapor.

Because the hydrogen can only be formed as a result of the decomposition of water vapor at altitudes above 25 km, some of the hydrogen in the northern hemisphere is transferred to the southern hemisphere. Due to this, the ozone formed above the high latitudes in the southern hemisphere remains without contact with another element and thus the ozone layer stabilizes. Conditions change during the summer in the Southern Hemisphere. In the perihelion of Mars there was an increase in dust activity in the atmosphere. The upper atmosphere is warming. This warming increases the height at which the atmosphere becomes saturated with water from an altitude of 40 km and allows it to contain an amount of water several times greater than that in the Aphelion.
The production of a large amount of hydrogen due to the decomposition of water vapor causes a stronger flow of ozone-depleting radicals towards the North Pole in its winter season, greater than its counterpart in the aphelion at its South Pole. This process causes the rate of ozone depletion to be 100 times greater over the North Pole in winter than its counterpart at the South Pole.

the mass of the atmosphere
The mass of the atmosphere depends on the seasons. In winter, part of the atmosphere recondenses into frost and ice at the North Pole. This seasonal precipitation can reach up to a latitude of 45 degrees north and the thickness on the ground can reach a height of one meter(2).
Circulations in the atmosphere
In an article published in the Research Journal of Geophysical in March 2012 (3), researchers reported the first discovery of the emission of infrared radiation at a wavelength of 1.27 microns above the poles in winter. This emission was observed during the years 2004-2006 in 40 observations. Emission of infrared radiation in planets whose atmospheres are common. In the upper layers of the atmospheres on Venus and Mars, the 2CO and nitrogen (2N) molecules are broken down by the ultraviolet radiation coming from the sun into oxygen and nitrogen atoms in the layer of the atmosphere known as the thermosphere at altitudes between 80-90 km, during the daytime. The emission of NO in the Martian atmosphere was discovered in 2005. Since this process is also typical for circulations in the atmosphere, there were researchers who expected 2O emission but there was no confirmation of this from the excited oxygen molecules until the report in 2010.
It was estimated that the infrared emission of the oxygen on the night side of Mars could be caused by a slow descent of the cold air towards the ground. This means fewer recombinations of oxygen atoms and a weaker bombardment of ultraviolet radiation from the sun that weakens the rate of decomposition. According to the researchers' assessment, the light emissions from the atmosphere are related to the circulation of the atmosphere. It may be that the warm air rises in the summer season above the pole in the atmosphere moves to the equator and sinks near the winter at the opposite pole. On the night side of Mars. This circulation takes the form of a Hadley cell, very similar to what happens on Earth on both sides of the equator. The oxygen atoms are transported in one large Hadley cell. The oxygen atoms re-create oxygen molecules during the descent of the Hadley cell at an altitude of 30-50 km.

Water vapor in the atmosphere

In a report published in September 2011, it was stated that the atmosphere is largely saturated with water vapor (4). It was a surprise. Until then, most measurements of Mars from spacecraft focused on the ground itself and few on the vertical structure of the atmosphere. This time a lot of time was devoted to the vertical measurements of the atmosphere. The research was done shortly before sunset or shortly after sunrise, when Mars still obscures the Sun. This technique allows vertical measurement of some components in the atmosphere such as water vapor. Measurements made during the spring and summer in the Northern Hemisphere showed that the vertical explosion of water vapor in the atmosphere is very different from what was thought until then.

The total amount of water vapor in the atmosphere of Mars is 10,000 times smaller than that of the Earth (do not forget that the density of the atmosphere of Mars is 1% of that of the Earth). On Earth, when the temperature in the atmosphere drops below the dew point, the water vapor condenses around small dust particles, aerosols or salt. In this situation the atmosphere becomes saturated with moisture that it cannot contain anymore. At this temperature and atmospheric pressure, water vapor passes the dew point. In a normal state, they condense and form water droplets or ice crystals. However supersaturation can occur when some of the water vapor remains in the atmosphere instead of condensing or freezing. When the condensation nuclei are too rare, the condensation starts to interfere and leaves too much water vapor in the air.

This process served as a model for understanding the Martian atmosphere. Until these measurements, it was believed that supersaturation could not exist on Mars. It seemed that every drop of water that passed the great saturation point would end up turning into ice. The measurements showed that great saturation occurs frequently in the center of the atmosphere up to a height of 50 km above the ground, when Mars is at its ephelion. The saturation rate found was up to 10 times higher than that of Earth. The vertical explosion of water vapor is a key factor in understanding the hydrological cycle of Mars, its climate and the transfer of water from one hemisphere to another. The findings raise the possibility that more water vapor is transported to a height that allows it to be broken down by the sun's ultraviolet radiation. This disintegration can mean that after the atomic disintegration, the hydrogen and oxygen can escape into space. This process has great significance in terms of water loss and the long-term development of the surface and the atmosphere. This may also have a significant connection to the processes that led to the depletion of the Martian atmosphere (the author's hypothesis - Haim Mazar).

dust in the atmosphere

In the atmosphere there are two types of dust particles, coarse particles with a diameter of 1.2 micrometers and smaller, finer particles with a diameter of 0.04 - 0.07 micrometers. The density of both types of particles in the atmosphere is small. The denser dust layer, its height from the ground is 20-30 km. The density of the fine dust particles is 3,000 per cubic meter and of the coarse dust particles is no more than two particles per cubic meter. Since the fine particles are in the upper layers of the atmosphere, the formation of ice is fast and this in turn affects the formation of clouds. The clouds are responsible for the precipitation and the temperatures of the ground despite their size and density. These particles are very important in shaping the climate of Mars. Despite the tiny size of the dust particles, the dust storms (dust devils) can lift large quantities from the ground into the air(5).
climate

According to the findings, the climate on Mars was in the past more dynamic than was thought until then. Examination of photographs taken by the MRO spacecraft from 2008 showed that the thickness of the ice layer is at least 100 km and most likely in the middle latitudes, the ice layer in the last 2.5 million years was probably 10 km. It is estimated that there was a flow of glaciers in certain areas in the last 100-6 million years. The significance of these findings is that the climate changed several times and that there were several ice ages (XNUMX).
water
The Vallis Reul landform looks like a river. It is believed that in the past a lot of water flowed in this place and they designed it. The length of this configuration is 1,500 km and many tributaries surround it. The slopes of the formation are sharp and steep and along its entire length many strips are visible at the bottom. The resulting impression is that these strips were formed by rocks, rock fragments and ice that were washed away by water. Throughout the Amazonian period which continues even today. In one of the photographed sections of the formation it is 7 km wide and 300 meters deep (7). In a part of Vallis Kasei, you see an area with an area of ​​1.55 million square kilometers in which channels were created by very strong water floods. This is one of the largest crater systems on Mars (8). There are places in the Arctic such as the Tenuis Rupes slope where the seasonal 2 CO ice sheet is covered by water frost at certain times in the spring. This layer, which is a few millimeters thick, is sometimes removed by the winds and reveals the 2 CO (2) ice layer.

to the second part of the review

Sources
1. "A seasonal ozone layer over the martian the south pole" 29.9.2013
http://scin.esa.int/mars-express/52881-a-seasonal-ozone-layer-over-the-martian-south -pole/
2. "Mars' northern polar region in transition" 5.8.3011
http://scin.esa.int/SPECIALiTS/Mars_Express/SEMA4VITPQG_2.html
3. "Glow in the Martian night throws light on atmospheric circulation". 27.3.2012
http://www.marsdaily.com/reports/Glow_In_The_Martian_Night_Throws_Light _On_ Atmospheric_Circulation_999.html
4. "Mars Express finds water super saturation in the atmosphere" 30.9.2011
http://www.marsdaily.com/reports/Mars_Express_Finds_Water_Super_saturation _In _The _Atmosphere_999.html
5. "New type of dust in Martian atmosphere discovered" 1.7.2014
http://www.marsdaily.com/reports/New_Type_Of_Dust_In_Martian_Atmosphere_ Discovered_999.html
6. "The ancient glaciers of Mars - is the red planet between ice ages?" 1.11.2012
http://www.dailygalaxy.com/my_webblog/2012/11/the-ancient-glaciers-of-mars-in-the- red-planet-between-ice-ages.html
7. "Reull Vallis: A river ran through it" 23.1.2013
http://www.marsdaily.com/reports/Reull_Vallis_A _River_ Ran_ Through _It_999.html
8. "The flood water of Mars" 7.6.2013
http://www.marsdaily.com/reports/The_Flood_Water_Of_Mars_999.html